1. Field of the Invention
The present invention relates to a lubricant injector for an apparatus for lubricating moving points of lubrication, especially rollers of a chain conveyer where the bearings of the rollers can be refilled with lubricant via a lubricant fitting on which the injector can be pressed during the lubricating process. The injector has a housing with an inlet for receiving lubricant and an injector tip for placement on the lubricant fitting, with a spring-loaded feed piston being disposed in the housing and serving to transfer lubricant from the inlet to the injector tip. The present invention also relates to an apparatus for lubricating moving points of lubrication, especially a central lubricating unit for rollers of a chain conveyer.
2. Description of the Prior Art
A central lubricating unit of this general type is known for lubricating the support rollers of a chain conveyer with which automobile body parts from a paint shop are introduced into a furnace for baking the paint. Due to the thermal stresses and the therewith connected evaporation of a roller bearing that is permanently filled with lubricant, it is necessary, in conformity with need, that the bearings of the supporting rollers be provided with a measured quantity of lubricant in order for the chain to rotate. For this purpose, a central nipple or fitting is provided in the roller support or on the roller pin, with this fitting supplying lubricant for the bearing to the interior of the associated roller via a transverse bore when lubricant under pressure is supplied via an injector that is placed on the fitting. The heretofore known injector of such a central lubrication unit has, in a housing, a feed piston that is actuated by compressed air and with which a predetermined amount of lubricant can be discharged via the injector tip to the lubricant fitting. A check valve is disposed in the injector tip. In the relief cycle, the piston is again moved into its rest position via a compression spring, whereby lubricant again flows to the feed piston. The drawback to this known design is that the entire injector must be moved, the feed piston is actuated with air, and the injector has a tendency to drip, since the residual lubricant that remains in the injector tip ahead of the check valve is discharged in an undesirable manner, especially because due to refilling of the injector with lubricant, the lubricant pressure is transmitted to the injector tip via the check valve, which is never completely sealed off, hence causing the residual lubricant to be discharged. In the aforementioned unit, such lubricant drops damage the quality of the paint job of the automobile body parts, and thus lead to rejection of the latter. A further drawback is that control of the lubrication process is imprecise, and in particular the timely connection of the injector with the fitting, and the positioning of these two parts, are unsatisfactory.
It is an object of the present invention, while avoiding the aforementioned drawbacks, to provide a lubricant injector as well as a lubricating apparatus, with which it is possible to precisely measure-out the discharged quantities of lubricant, without residual dripping, not only for oil but also for fluid grease, and with which the lubricating process is improved considerably, especially with regard to synchronizing the parts that are to moved together, and with regard to precisely positioning parts relative to one another.